from entered a Home Depot contest and hit on the idea of stenciling street art with hydrophobic NeverWet stuff, producing designs that are only visible when it rains.
Step 1: You need a stencil. You can do something simple or use an image that includes a fair amount of detail. I created my own stencils from cardboard, but there's no reason you can't use a ready-made or store-bought stencil. Just know that NeverWet will get sprayed on that, too.
Step 2: Place stencil on concrete. I recommend that you only try this on light-colored concrete for best results. I also used a repositionable adhesive spray on the back of my stencils to keep them securely in place. Depending on the complexity and material of your stencil, you may be able to get away with just using tape to hold it down, or maybe using nothing at all. If your stencil is as complicated as mine pictured above, you'll definitely need to adhere it down.
Step 3: Spray the NeverWet into the cut-out areas of your stencil according to the manufacturer's instructions found on the label. I did two base coats and two top coats.
Step 4: After waiting for the recommended amount of time (see NeverWet instructions), remove your stencil. If you look closely, you will probably be able to see the light, translucent residue that the NeverWet leaves behind.
Make Rain Drawings with NeverWet! (Thanks, Bloo!)